Sediment Control Mechanism of Debris Dam

本课题从泥沙水力学的角度分析了泥石坝的拦沙机理。选择了实际河流资料分析、泥石坝侵蚀控制机理和坝体上下游泥沙输移机理三个课题进行了研究。研究结果表明：(1)收集和分析了天龙江支流科什布河的河床变化资料，为泥石坝建设的河流提供了有价值的河床变化信息。通过对金松江支流阿夏拉来河泥石流特性的观测研究，阐明了泥石流的泥沙淤积规律。(2)从坝口宽度和坝高两个方面，从试验和理论上探讨了坝体上游河床变化与坝体输沙率的关系。建立了泥石流控制的数学模型，该模型可用于预报泥石流的河床变化和出沙与来沙的比例。(3)从不同类型的开敞式泥石坝出发，讨论泥石流的控制机理，并阐明泥石流的控制机理。

This project has been made to analyze the sediment control mechanism of debris dam in terms of sediment hydraulics. Three subjects, which are concerning the data analysis of actual river, the erosion control mechanism of debris dam and the mechanism of sediment transportation upstream and downstream of the dam, are chosen for consideration. The results show(1) Data on bed variation of the Koshibu River, tributary of the Tenryu River, are collected and analyzed, and give a valuable information of bed variations in rivers where debris dams are constructed. Observational study is made in the Ashiarai River, a tributary of the Jintsu River, for the behavior of debris flow in the crib dam, and clarifies the sediment deposition from the flow.(2) The relation between bed variations upstream of dams and sediment discharge rates from dams is discussed experimentally and theoretically in terms of widths of opening and heights of dams. A mathematical model, which is useful for the predictions of bed variation as well as of the ratio of outflowing sediment discharge to the inflowing one, is presented.(3) The mechanisms of debris flow control are discussed in terms of open type debris dams of various kinds, and are clarified.